what the FVCK is wrong with my car?

**White5.0** · 05-05-2009, 07:43 PM

ok. 87 GT converted to mass air. gt40p heads, cobra intake, 24 lb injectors, t5 etc.

-if i have my EGR on but vacuum plugged on the valve and under the intake, the idle will surge, rpms will hang, car will stall when stopping at a stop sign/red light.

-if i hook up the EGR valve directly to the intake manifold for vacuum, it will idle like a champ, no surging, no stalling. BUT it runs like SH1T and there is hesitation when giving it throttle.

what the FU CK is wrong with my car? i pulled the upper intake, retorqued the lower intake bolts, put ALL NEW vaccum lines and made sure everthing was tight as hell. i am 99.999999999999999999% sure there is no vacuum leak.

so wtf?....i have only 300 miles on my car since i rebuilt the whole engine and they've all been bullshit miles because i havent been able to enjoy my car without any problems yet. im pissed. where else can i look?

**White5.0** · 05-05-2009, 08:01 PM

oh yeah also wanted to add that it has a brand new IAC and tps voltage is at .98v with key on, engine off.

im thinking maybe mass air meter? ill try cleaning it but its raining now so it'll have to wait

**silvernotch** · 05-05-2009, 08:04 PM

nephew's car did same thing with running like crap. mass air meter fixed his car.

**RAYZ02GT&93LX** · 05-05-2009, 09:03 PM

Are you running a aftermarket cam?

**White5.0** · 05-05-2009, 09:06 PM

just a b303, dont think thats a problem tho

**wick** · 05-05-2009, 09:10 PM

Originally Posted by silvernotch

nephew's car did same thing with running like crap. mass air meter fixed his car.

**97LaserRed** · 05-05-2009, 09:20 PM

Ya I would try maf. I heard that company sell junk products maybe the sensors are bad too. What does everyone else run on their 5.0s?

**White5.0** · 05-05-2009, 09:30 PM

Originally Posted by 97LaserRed

Ya I would try maf. I heard that company sell junk products maybe the sensors are bad too. What does everyone else run on their 5.0s?

ya i have a stupid granatelli MAF, bought it used ... most people go with the pro-m or pmass.

**White5.0** · 05-05-2009, 09:32 PM

anyone got a 24lb mass air meter i can try out to see if that is the problem?

**97LaserRed** · 05-05-2009, 09:36 PM

I heard good things about pmass

**lib88stang** · 05-05-2009, 09:57 PM

unplug the iac to see what happens

**White5.0** · 05-05-2009, 10:02 PM

Originally Posted by lib88stang

unplug the iac to see what happens

ive tried that before, it still runs, doesnt die. ive done a base idle reset before as well.

ok and looking at this vacuum diagram:
http://www.veryuseful.com/mustang/te...g5.0Vacuum.gif

i pretty much have nothing from the left side of that pic lol. i have an EGR block off plate on, removed all the stuff from the passenger side strut tower (TAB, TAD, and EVR i think), and have no smog pump or vapor canister. i was told this is all ok though?

also, where is the vacuum check valve supposed to be located?

**crazylou** · 05-05-2009, 10:08 PM

sounds like mass air, could bought a (USED) junk one...UNLESS U KNO IT WORKED FOR A FACT...

**White5.0** · 05-05-2009, 10:09 PM

Originally Posted by crazylou

sounds like mass air, could bought a (USED) junk one...UNLESS U KNO IT WORKED FOR A FACT...

nah im not sure if it worked or not i bought it from some rando

**crazylou** · 05-05-2009, 10:09 PM

That Would B The First Place I Would Start...

**lib88stang** · 05-05-2009, 10:16 PM

what happens when you unplug the mass? and was it coverted to mass before this engine swap?

**crazylou** · 05-05-2009, 10:17 PM

If I'm Not Mistaken U Should B Able 2 Use A Stock 1 2 C If Its The Problem...only 24lb Inj Not Like Their 60's Or Sumthing...
Sum1 Correct Me If I'm Wrong...think I Have Stock 1 U Can Try, Have 2 C If I Do Have One 2mar...

**White5.0** · 05-05-2009, 10:39 PM

Originally Posted by lib88stang

what happens when you unplug the mass? and was it coverted to mass before this engine swap?

havent tried unplugging mass air meter. when i do this should i see how it idles or actually take it for a drive with it unplugged?

and the conversion was done before the swap and supposedly worked just fine. i bought the car as a roller with A9P(or L i cant remember) and harness already in it.

**349Stroker** · 05-05-2009, 11:15 PM

unplug meter and see what happens

make sure mass air meter is getting voltage.If the conversion wasn't done right and has a loose or diconnected wire it might not run right

the egr has nothing to do with this.I don't run egr valves and all my cars ran fine